This invention relates generally to rock drills and more particularly to rock drills that are percussive, fluid-actuated drills.
U.S. Pat. No. 5,085,284 claims a hybrid, pneumatic percussive rock drill wherein the point of admission of fluid into a drive chamber is controlled by a valve whose opening and closing is pressure sensitive. From the stand point of efficient use of fluid, it would be desirable to be able to control even more precisely the point in the drive stroke that the valve closes to shut off flow of percussive fluid to the drive chamber.
The foregoing illustrates limitations known to exist in present fluid-actuated percussive rock drills. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.